Re: [PATCH 1/2] dt-bindings: iio: adc: Add TI ADS1220

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
- [High] The `diff-channels` property constraint uses invalid YAML flow sequence syntax (`items: [const: 0, const: 1]`) that will cause a fatal parser error or evaluate to a single-element list with a collapsed duplicate dictionary key.
- [Medium] The child node regex and `reg` maximum artificially limit the device tree to defining at most 7 channels, despite the hardware supporting 12 unique multiplexer configurations.
--

commit 2b3665a0096105a4bb2db6266e47dec0a0802cff
Author: Nguyen Minh Tien <zizuzacker@gmail.com>

dt-bindings: iio: adc: Add TI ADS1220

This commit adds a device tree binding for the TI ADS1220 24-bit ADC.
It describes the SPI device, its per-input channel child nodes,
external reference selection, and the DRDY interrupt.

> diff --git a/Documentation/devicetree/bindings/iio/adc/ti,ads1220.yaml b/Documentation/devicetree/bindings/iio/adc/ti,ads1220.yaml
> new file mode 100644
> index 0000000000000..1fedffc2a1475
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/adc/ti,ads1220.yaml
[ ... ]
> +patternProperties:
> +  "^channel@[0-6]$":
> +    $ref: adc.yaml
> +    type: object
> +    description: Represents one ADC input configuration (channel).
> +
> +    properties:
> +      reg:
> +        minimum: 0
> +        maximum: 6

[Severity: Medium]
The ADS1220 hardware supports 12 unique multiplexer combinations
(8 differential pairs and 4 single-ended inputs). Does this regex and
reg maximum artificially limit the device tree to defining at most 7
channels?

System integrators might not be able to represent all available
hardware configurations if this limit is enforced.

[ ... ]
> +      diff-channels:
> +        description:
> +          Differential input pair routable by the ADS1220 multiplexer.
> +        oneOf:
> +          - items: [const: 0, const: 1]
> +          - items: [const: 0, const: 2]
> +          - items: [const: 0, const: 3]
> +          - items: [const: 1, const: 2]
> +          - items: [const: 1, const: 3]
> +          - items: [const: 2, const: 3]
> +          - items: [const: 1, const: 0]
> +          - items: [const: 3, const: 2]

[Severity: High]
Will this syntax pass the dt_binding_check validation?

In YAML, a flow sequence like [const: 0, const: 1] evaluates to a list
containing a single implicit mapping with duplicate keys. The dt-schema
toolchain utilizes a strict parser that typically fails on duplicate
dictionary keys.

If it did parse, it would likely collapse the duplicate keys into a
single element, forcing the diff-channels array to have exactly one
element instead of the expected two.

Would it be better to use a valid flow mapping sequence, such as
- items: [{const: 0}, {const: 1}]?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260610151342.44274-1-zizuzacker@gmail.com?part=1